 * {
   margin: 0;
   padding: 0;
 }

 html,
 body {
   width: 100%;
   height: 100%;
   font-size: 20px;
   font-family: '楷体';
 }

 .main {
   width: 470px;
   height: 100px;
   position: fixed;
   top: 50%;
   left: 50%;
   transform: translate(-50%, -50%);
   border: 1px solid deepskyblue;
   padding: 20px;
 }

 #pre,
 #city,
 #area {
   width: 100px;
   height: 30px;
   text-align: center;
   line-height: 30px;
   cursor: pointer;
   color: rgba(0, 0, 0, .8);
 }